What Is Rmv In Diving?

Respiratory Minute Volume (RMV) is a measure of the amount of gas consumed by a diver during a dive, expressed as a volume. It is often confused with Surface Air Consumption (SAC) rate or Surface Consumption Rate (SRC). RMV is calculated from submersible pressure gauge (SPG) readings before and after the dive, the cylinder size, and the average depth and dive time. It is measured in litres per minute.

In SCUBA diving, RMV is crucial for cylinder planning and enhanced safety. It is also known as Surface Air Consumption (SAC) rate or Surface Consumption Rate (SRC). The IMCA recommends RMV = 35 Lmin for working commercial divers and 40 Lmin for emergencies. Decompression is usually less for non-working hard divers, as RMV is usually less.

The IMCA also suggests that RMV = 40 Lmin for emergencies due to less decompression. For a working commercial diver, RMV = 35 Lmin, while for emergencies, RMV = 40 Lmin.

RMV is a vital aspect of scuba diving, as it measures the volume of breathing gas that enters the surface air consumption (SAC) unit. It is typically expressed in cubic feet per minute. RMV rates are essential for scuba diving gas planning and understanding the importance of air consumption to enhance dive performance.

In summary, RMV is a crucial measure of gas consumption during a dive, and its calculation can help divers plan their dives more effectively.

What is the 120 rule in scuba diving?

For shallower depths, or deeper depths, the 120 rule was quite conservative…for example it would suggest 10 minutes at 110 ft and zero minutes at 120 ft, whereas the actual table gave 20 and 15 minutes, respectively, at 110 and 120 ft. So, the rule of 120 kept you “safe.” It was for the first dive, only.

(This is an updated version of a post made 4 1/2 years ago….)

You will sometime hear divers (especially older ones) refer to the Rule of 120. this was an approximation to working out No-Decompression-Limits based on the old U.S. Navy tables. The “Rule of 120” was based on the sum of depth (in feet) and NDL (in minutes), which turned out to be 120 for the old Navy tables, exact between 60 and 90 ft. For shallower depths, or deeper depths, the 120 rule was quite conservative…for example it would suggest 10 minutes at 110 ft and zero minutes at 120 ft, whereas the actual table gave 20 and 15 minutes, respectively, at 110 and 120 ft. So, the rule of 120 kept you “safe.” It was for the.

, only. It was even printed on the watchbands of the day. You who are mathematically inclined will recognize this as a tangent-linear approximation to the deco curve.

What is RMV rate diving?

RMV rate is a measurement of the breathing gas that a diver consumes in one minute on the surface. RMV rates are expressed in cubic feet per minute (imperial) or liters per minute (metric),

Unlike a SAC rate, an RMV rate can be used for calculations with tanks of any volume. A diver who breathes 8 cubic feet of air a minute will always breathe 8 cubic feet of air a minute regardless of the size of the tank holding the air.

So most divers remember their air consumption rates in RMV format. Gas planning is typically worked through in RMV format and then converted to either psi or bar based on the type of tank to be used.

Every training manual lists a slightly different method of gathering the data to calculate a diver’s air consumption rate. Whichever one you choose, remember to enter the water and allow your tank to cool before beginning your data gathering. As your tank cools, the pressure shown on your submersible pressure gauge (SPG) might drop 100 or 200 psi. Failing to account for this drop in pressure will result in calculating an inaccurately high air consumption rate.

What does RMV stand for diving?

Respiratory minute volume (RMV) is the volume of gas that is breathed by a diver in a minute. For a working commercial diver IMCA suggests RMV = 35 L/min. For emergencies IMCA suggests RMV = 40 L/min Decompression RMV is usually less as the diver is not generally working hard.

Scuba gas planning is the aspect of dive planning and of gas management which deals with the calculation or estimation of the amounts and mixtures of gases to be used for a planned dive. It may assume that the dive profile, including decompression, is known, but the process may be iterative, involving changes to the dive profile as a consequence of the gas requirement calculation, or changes to the gas mixtures chosen. Use of calculated reserves based on planned dive profile and estimated gas consumption rates rather than an arbitrary pressure is sometimes referred to as rock bottom gas management. The purpose of gas planning is to ensure that for all reasonably foreseeable contingencies, the divers of a team have sufficient breathing gas to safely return to a place where more breathing gas is available. In almost all cases this will be the surface.

Gas planning includes the following aspects:: Sect.3.

• Choice of breathing gases
• Choice of scuba configuration
• Estimation of gas required for the planned dive, including bottom gas, travel gas, and decompression gases, as appropriate to the profile.
• Estimation of gas quantities for reasonably foreseeable contingencies. Under stress it is likely that a diver will increase breathing rate and decrease swimming speed. Both of these lead to a higher gas consumption during an emergency exit or ascent.
• Choice of cylinders to carry the required gases. Each cylinder volume and working pressure must be sufficient to contain the required quantity of gas.
• Calculation of the pressures for each of the gases in each of the cylinders to provide the required quantities.
• Specifying the critical pressures of relevant gas mixtures for appropriate stages (waypoints) of the planned dive profile (gas matching).

Which is better PADI or NAUI?

Differences. Both NAUI and PADI are two of the most prestigious diving certification agencies worldwide that offer diving courses. Both are always enhancing knowledge and skills while ensuring that it is done safely.

NAUI will teach divers how to save an unconscious diver during the early courses, and PADI does not offer that.

NAUI is a not-for-profit agency, and its main focus is to make sure that all divers are well educated about safety during diving. Their motto is “Dive safety through education.” US Navy uses NAUI certification.

PADI, on the other hand, is a for-profit organization that profits mainly from marketing and selling their products. It has also trained divers all over the world.

Does sac rate increase with depth?

Depth:. The deeper we go, the more compressed the air becomes and so we consume more of it for each breath. At the surface, we might consume 1.5 litres of air in a breath, but at 20 meters deep this has turned into 4.5 litres.

Stress:. The biggest influence, as we get stressed, we subconsciously increase our breathing rate and heart rate. Unfortunately, this can be a vicious circle as your nervous system becomes more active and your awareness decreases. This means you can get more anxious and the cycle keeps on going. A stressed diver could be breathing three times as much as a relaxed diver.

Exercise:. A basic requirement is that as we exercise aerobically, our muscles need the oxygen to convert stored sugar and fatty acids to create energy. More exercise means more oxygen required and more air breathed in to provide it. Fin against a current for a while and you’ll quickly start to see your air consumption go up. Do a drift dive where you are gliding along and it is totally the opposite.

Is Tom Cruise scuba certified?

• Tom Cruise: He is known to be an avid scuba diver and has often been spotted diving in various locations around the world. He reportedly obtained his diving certification in the 1990s.
• Leonardo DiCaprio: DiCaprio is not only passionate about environmental causes but is also a certified scuba diver. He has dived in different parts of the world and has used his platform to raise awareness about ocean conservation.
• Jessica Alba: Alba is another celebrity known for her interest in scuba diving. She has frequently mentioned her love for diving and has been spotted enjoying the underwater world on vacations.
• Chris Hemsworth: The “Thor” actor is known for his adventurous spirit, and scuba diving is one of his hobbies. He has shared photos of his diving experiences on social media.
• Will Smith: Smith has talked about his love for scuba diving in interviews and has shared his diving experiences through social media. He often explores the underwater world during vacations.
• James Cameron: The acclaimed filmmaker is not just interested in diving but is a deep-sea explorer. He’s known for his record-setting dives and his passion for underwater exploration, as seen in his films like “The Abyss” and “Titanic.”
• Gisele Bündchen: The supermodel has been spotted enjoying scuba diving on vacations and has posted about her diving experiences on social media.
• Jason Momoa: The “Aquaman” star has a strong connection to the ocean and is passionate about diving. He’s often seen exploring the underwater world and has expressed his love for diving in interviews.
• Natalie Portman: Portman is not only an accomplished actress but also a certified scuba diver. She has shared her experiences diving in different parts of the world.
• Bear Grylls: The survival expert and TV personality, known for his adventurous spirit, is also a keen scuba diver. He has explored various underwater environments during his expeditions.
• Penélope Cruz: Cruz is known to enjoy scuba diving and has been seen indulging in this activity during vacations.
• Prince William: The Duke of Cambridge is a certified diver and has been spotted diving in different locations. He is known to have a passion for marine conservation and has supported several initiatives in this field.
• Julia Roberts: Roberts has expressed her love for scuba diving in interviews and has been seen enjoying diving vacations with her family.
• Liam Neeson: The actor is a certified scuba diver and has occasionally spoken about his interest in diving and exploring the underwater world.
• Ewan McGregor: McGregor is an enthusiastic diver who has dived in various locations and often incorporates diving into his travels and adventures.
• Shakira: The singer has shown interest in scuba diving and has shared pictures of her diving experiences on social media.
• Adriana Lima: The supermodel has mentioned her passion for scuba diving and has been seen enjoying diving during her leisure time.
• Justin Bieber: The pop sensation has been spotted scuba diving on multiple occasions and has shared pictures of his diving adventures on social media.
• Katy Perry: Perry has expressed her love for scuba diving and has enjoyed diving during vacations, often posting about her underwater experiences online.
• Will Ferrell: The comedian and actor is a certified scuba diver and has talked about his interest in diving in interviews.
• Michael Phelps: The Olympic swimmer and most decorated Olympian of all time is also a scuba diving enthusiast. He often shares his diving experiences on social media.; Pierce Brosnan: The former James Bond actor has been seen enjoying scuba diving and has spoken about his passion for diving in interviews.; Dwayne “The Rock” Johnson: Johnson has been photographed scuba diving in various exotic locations and has mentioned his love for diving during interviews.; Cristiano Ronaldo: The soccer superstar has been seen diving and snorkeling during vacations and has shared glimpses of his underwater adventures online.; Kate Winslet: The Academy Award-winning actress is a certified scuba diver and has expressed her passion for diving and exploring the underwater world.; Chris Pratt: The actor has spoken about his interest in scuba diving and has shared photos of his diving experiences on social media.; Orlando Bloom: The actor has been frequently seen diving in various locations and has a strong passion for underwater exploration.; Jessica Biel: Biel is known to be a certified scuba diver and has mentioned her love for diving in interviews.; Matt Damon: Damon has talked about his scuba diving adventures in the past and has been spotted diving on vacations.; Emily Blunt: The actress has shown interest in scuba diving and has enjoyed diving experiences in different parts of the world.; Robert Redford: Redford has been known to enjoy scuba diving and exploring the ocean. He has mentioned his fascination with the underwater world in interviews.; Ben Stiller: Stiller has expressed his love for scuba diving and has been seen diving during leisure time.; Richard Branson: The business magnate is an adventurous spirit and has been seen diving and exploring the underwater world around his private island.; Sir Paul McCartney: The legendary musician and former member of The Beatles has been known to enjoy scuba diving and has engaged in diving activities during vacations.; Kate Hudson: Hudson has mentioned her interest in scuba diving and has been spotted diving on various occasions.; Mark Ruffalo: The actor has shown an interest in scuba diving and has spoken about his experiences diving in different locations.

These celebrities, among others, have expressed their fascination with scuba diving and often use their influence to raise awareness about ocean conservation and the beauty of marine life.

Can you free dive 130 meters?

Breaking Down Alexey Molchanov’s Freediving World Record. To prove our point, let’s take a look at Alexey Molchanov. The Russian diver dove 130 meters with one breath, while wearing a monofin. That’s 426 feet, and a world record!

This record-breaking dive took him 39 stories underwater, and he had to hold his breath for almost five minutes.

How did he manage to do this and live to tell the tale? Let’s take a look.

What is SAC vs RMV scuba?

SAC and RMV. SAC stands for Surface Air Consumption and RMV for Respiratory Minute Volume. Your SAC rate is to measure the amount of gas consumed in bar while you are breathing for one minute on the surface. While the RMV measure the amount of gas consumed in liters per minute on the surface. Note, in our examples we will use the metric system, meter, bar and l/min.

Keep in mind, that your SAC rate is cylinder specific. If your SAC rate was based on the use of a 12 liter cylinder but you change for example to a 15 liter, than you need to recalculate your SAC rate.

The benefit of knowing how to calculate SAC and RMV rate is that you can use these values during your dive (gas) planning. This is as well for a recreational as for a technical diver an important aspect because running out of gas is one of the most common issues in diving incidents.

How do you calculate SAC for diving?

The SAC formula helps a diver understand, on an average basis, what their air consumption will be at a given depth. This allows the diver to better plan how long their dive can be, giving two points for dive turn times: no decompression times and available air. The SAC formula is: SAC = (PSI at depth used/time) x 33/(depth+33)). To perform this in metric units, use bar instead of PSI and 10 instead of 33.

An exercise to perform which helps plan air consumption in various conditions such as currents, high workloads etc is to find a site where you can sit in one atmosphere of water (10 metres / 33 feet) and take three samplings of air consumption: resting, moderate workload and high workload. For the resting, using a slate to note your starting air pressure and sit or swim very lightly for 3-5 minutes, then note ending pressure. For the moderate workload exercise follow the same air pressure noting procedures, but this time swim at a moderate pace making sure to stay a depth of 1 atmosphere. For the high workload exercise, find an object such as a rock or wreck (something that will not move and where you will not damage marine life) note your starting pressure and place your hands on the object and try to push it while swimming, after 3-5 minutes note your ending air pressure. After performing these three exercises, you will have a clear picture of air consumption rates for low, medium, and high workloads.

The purpose and importance of incorporating air consumption into your dive plan is that the only reason you are able to stay underwater for a prolonged period of time is the air you have in your cylinder. If you do not know how long your air supply will last, or you are not tracking your air during the dive, you could run out and risk serious injury from a rapid ascent or not having enough air to perform a proper safety stop. In days past running low or out of air was a function of the equipment at the time (no SPG or dive computers) the limited knowledge available to sport divers and scuba equipment that was not built as well as it is today. Those times and reasons are far behind, and now a days there is no excuse for running out of air.

What is a normal SAC rate?

Frequently Asked Questions. What is a SAC rate?. SAC, which stands for Surface Air Consumption, refers to the amount of air a scuba diver breathes in one minute while on the surface. This measurement is typically expressed in cubic feet per minute (cfm) or liters per minute (lpm). A diver’s SAC rate can vary depending on factors such as their fitness level, breathing technique, and the type of diving they engage in. For experienced scuba divers, a typical SAC rate falls between 0.5 and 1.0 cfm. Understanding and monitoring one’s SAC rate is crucial for safe and efficient diving.

How does a scuba diver determine his SAC rate?. To determine the Surface Air Consumption (SAC) rate, a scuba diver records the starting and ending air pressure in their tank (in psi or bar) before and after the dive. They also note the total bottom time (in minutes) and average depth, which is then converted to ambient pressure in atmospheres absolute (ATA). The SAC rate is calculated by subtracting the ending tank pressure from the starting pressure to find the total air used, dividing by the dive time to get the air used per minute, and then dividing by the ATA to adjust for depth. This reflects the amount of air the diver would use per minute at surface pressure.

Is the Avelo Dive System suitable for beginners?. Absolutely! The Avelo Dive System is designed to benefit both novice and advanced divers. For beginners, it offers smoother, more controlled breathing, helping you gain confidence underwater. For advanced divers, it allows them to explore deeper depths and stay underwater longer. To use the Avelo Dive System, all divers must first undertake an Avelo Speciality Diver Course (RAD)

What happens if sac is small?

Methods: 190 patients with a small gestational sac between 5.7 and 9.0 weeks’ gestation, defined as the mean sac diameter minus the embryonic size Results: The spontanenous abortion rate for those pregnancies between 5.7–9.0 weeks’ gestation with a small gestational sac (108/190; 57.0%) was significantly higher than for the control group (10/155; 6.5%) (p 35 years, first-trimester vaginal bleeding, mean sac diameter minus embryonic size Conclusions: The prediction of miscarriage from a small gestational sac between 5.7–9.0 weeks’ gestation is, at best, fair (miscarriage rate: 57.0%). If the pregnancy continues, the neonate is more likely to deliver prematurely and therefore, have a lower birth weight.

Identification. DOI: doi.org/10.1016/S0301-562900300-4.

• View Large Image
• Download Hi-res image
• Download.PPT